Composite Aircraft Core Structures with Integrated Moisture Drainage
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Solution Overview
Problem
Manufacturing composite core structures for aircraft components, such as landing gear doors and fairings, is challenging due to complex design requirements, tight tolerances, and issues like freeze-thaw cycles causing structural damage, leading to inefficiencies and waste.
Innovation Solution
A composite core structure with drainage paths and non-hexagonal cells, such as quadrilateral or rhombus-based prisms, that facilitate efficient moisture drainage and improved mechanical properties, using laminated composite materials and reversible sheet connections, simplifying manufacturing and reducing structural damage from freeze-thaw cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional composite core structures are used, then structural strength is maintained, but moisture accumulation causes freeze-thaw damage reducing structural integrity
Solution Approach 1:
The core structure incorporates drainage channels and void spaces within the honeycomb configuration that allow moisture to drain away from critical structural interfaces. The porous nature of the core material enables water to be channeled through designated paths to drainage holes, preventing accumulation that would cause freeze-thaw damage while maintaining the overall structural integrity of the composite panel.
Solution Approach 2:
The invention extracts and removes moisture from the core structure through integrated drainage systems. Drainage channels and holes are built into the core structure to actively extract water that enters through fastener holes or seals, preventing it from remaining trapped where it could cause harmful freeze-thaw effects.
2Manufacturing precision
If tight tolerances are imposed on composite core structures, then assembly precision is improved, but manufacturing complexity and waste increase
Solution Approach 1:
The core structure is divided into modular sections with standardized honeycomb cell configurations. This segmentation allows for pre-fabrication of core segments that can be precisely manufactured using automated processes, then assembled into the final structure. The modular approach maintains tight tolerances while reducing overall manufacturing complexity through standardization.
Solution Approach 2:
The invention changes the geometric parameters of the core structure, specifically using non-hexagonal cell configurations (such as rectangular or triangular cells) that are more amenable to automated manufacturing processes. This parameter change enables better control over manufacturing tolerances while simplifying the fabrication process compared to traditional hexagonal honeycombs.
3Ease of manufacture
If manual lay-up processes are used, then manufacturing flexibility is maintained, but productivity and efficiency decrease
Solution Approach 1:
The invention replaces manual mechanical lay-up processes with automated manufacturing methods. The core structure can be fabricated using automated fiber placement, resin transfer molding, or other automated composite manufacturing technologies. This substitution maintains design flexibility while dramatically improving productivity and reducing labor-intensive operations.
Solution Approach 2:
The core structure is designed with pre-integrated drainage channels and drainage holes that are formed during the initial manufacturing process rather than requiring post-assembly modifications. This preliminary action allows the drainage functionality to be built in during automated fabrication, eliminating subsequent manual steps and improving overall assembly efficiency.
4Shape
If pre-stress is built into the structure, then target shape is achieved, but manufacturing complexity increases
Solution Approach 1:
The core structure incorporates pre-formed drainage channels and drainage holes that are integrated into the manufacturing process. By establishing the drainage infrastructure during initial fabrication rather than adding it later, the manufacturing process achieves the target geometry with built-in functionality without requiring complex post-assembly operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances structural integrity by reducing moisture-induced damage, improves manufacturing efficiency, and reduces waste, while maintaining desired mechanical properties and flexibility, allowing for easier assembly and lower maintenance costs.
Implementation Method 1
The drainage path may extend parallel to the first body side and/or to the second body side... configured to allow fluid to drain from the core structure
Data Source
AI summary
A core structure (300) for a composite panel for an aircraft, for example a door fairing for a landing gear bay, including a sandwich structure in which core cells (301) are sandwiched between first and second body sides (skins 303, 305). The core cells are square or rectangular in shape and each have a void formed by cell walls (307). The first and second body sides and the cell walls include laminated composite material of multiple layers. Drainage holes (320) in the cell walls form one or more direct drainage paths (P2, P3) for the flow of fluid from the core structure. The core cells include first and second sheets of cells reversibly mounted to each other, such that the void of each cell is formed in part by the first sheet and in part by the second sheet.